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66 lines
1.7 KiB
Go
66 lines
1.7 KiB
Go
9 years ago
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package homebrew
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import (
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"fmt"
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"github.com/pd0mz/go-dmr/bit"
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"github.com/pd0mz/go-dmr/ipsc"
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)
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// ParseData reads a raw DMR data frame from the homebrew protocol and parses it as it were an IPSC packet.
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func ParseData(data []byte) (*ipsc.Packet, error) {
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if len(data) != 53 {
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return nil, fmt.Errorf("invalid packet length %d, expected 53 bytes", len(data))
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}
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var (
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slotType uint16
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dataType = (data[15] & bit.B11110000) >> 4
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frameType = (data[15] & bit.B00001100) >> 2
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)
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switch frameType {
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case bit.B00000000, bit.B00000001: // voice/voice sync
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switch dataType {
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case bit.B00000000:
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slotType = ipsc.VoiceDataA
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case bit.B00000001:
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slotType = ipsc.VoiceDataB
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case bit.B00000010:
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slotType = ipsc.VoiceDataC
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case bit.B00000011:
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slotType = ipsc.VoiceDataD
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case bit.B00000100:
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slotType = ipsc.VoiceDataE
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case bit.B00000101:
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slotType = ipsc.VoiceDataF
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}
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case bit.B00000010: // data sync
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switch dataType {
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case bit.B00000001:
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slotType = ipsc.VoiceLCHeader
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case bit.B00000010:
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slotType = ipsc.TerminatorWithLC
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case bit.B00000011:
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slotType = ipsc.CSBK
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case bit.B00000110:
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slotType = ipsc.DataHeader
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case bit.B00000111:
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slotType = ipsc.Rate12Data
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case bit.B00001000:
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slotType = ipsc.Rate34Data
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}
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}
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return &ipsc.Packet{
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Timeslot: (data[15] & bit.B00000001),
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CallType: (data[15] & bit.B00000010) >> 1,
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FrameType: (data[15] & bit.B00001100) >> 2,
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SlotType: slotType,
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SrcID: uint32(data[5])<<16 | uint32(data[6])<<8 | uint32(data[7]),
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DstID: uint32(data[8])<<16 | uint32(data[9])<<8 | uint32(data[10]),
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Payload: data[20:],
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PayloadBits: bit.NewBits(data[20:]),
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Sequence: data[4],
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}, nil
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}
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